Realistic cube rigid boy physics
Simply:


add a plane and set it to rigid body passive
add a cube somewhat over it, set it to rigid body active
just rotate the cube it a bit so that its bottom face is not exactly parallel to the plane... reality is never absolutely perfect. Adding to that, or otherwise, there are settings to make the plane more "bouncy" if you prefer: look under plane and cube rigid body settings and enhance "bounciness" (try 0.2- 0.4 to start for the cube, try 1 for the plane) at your taste.


Done, press ALTA



Obviously the bonciness depends also on the falling object shape: try a sphere...